τῇ γὰρ χάριτί ἐστε σεσῳσμένοι διὰ πίστεως καὶ τοῦτο οὐκ ἐξ ὑμῶν Θεοῦ τὸ δῶρον οὐκ ἐξ ἔργων,* ἵνα μή τις καυχήσηται αὐτοῦ γάρ ἐσμεν ποίημα κτισθέντες ἐν Χριστῷ Ἰησοῦ ἐπὶ ἔργοις* ἀγαθοῖς οἷς προητοίμασεν ὁ Θεὸς ἵνα ἐν αὐτοῖς περιπατήσωμεν.
For it is by grace that you are saved, through faith, and [this is] not of yourselves—[it is] the gift of God, not [the result] of works*: that no one may boast. For we are His workmanship, having been created in Christ Jesus for good works*, which God had prepared [for us] beforehand, that we should walk in them.
* the same word for 'work'—ἔργον ergon— differing only in grammatical function within the sentence.
From this it is clear that God does the saving. God's grace and mercy is the only reason anyone is saved. Good works cannot save anyone by themselves. No amount of other contexts may overwrite what is being claimed here: God saves man, man is powerless to save Himself. How God's grace saves man is not mentioned—the economy of God's saving is not detailed here. What is detailed is that God's grace necessarily causes good works in the believer:
We may draw a simple syllogism:
1) People who are ultimately saved, objectively, says Scripture, are created to do good works.
2) This means that good works and salvation are mutually entangled and therefore necessary.
3) Ergo (no pun intended), good works—working within the justified state—are necessary for salvation, not that they themselves cause it.
The meaning of the word here for 'work'—ἔργον ergon—can be clearly seen in its various translations (NASB): action (1), behavior (1), deed (13), deeds (52), doing (1), effectual (1), labor (1), result (1), task (1), what...done (1), work (34), works (62).
So anything less than 'good works' as an interpretation here should make one suspect theological bias. This is what the word means: doing good things.
This cannot be weakened by context, only who works, how/by what means or for what reason/toward what they work.
Ὥστε, ἀγαπητοί μου, καθὼς πάντοτε ὑπηκούσατε μὴ ὡς ἐν τῇ παρουσίᾳ μου μόνον ἀλλὰ νῦν πολλῷ μᾶλλον ἐν τῇ ἀπουσίᾳ μου μετὰ φόβου καὶ τρόμου τὴν ἑαυτῶν σωτηρίαν κατεργάζεσθε* Θεὸς γάρ ἐστιν ὁ ἐνεργῶν ἐν ὑμῖν καὶ τὸ θέλειν καὶ τὸ ἐνεργεῖν ὑπὲρ τῆς εὐδοκίας πάντα ποιεῖτε χωρὶς γογγυσμῶν καὶ διαλογισμῶν ἵνα γένησθε ἄμεμπτοι καὶ ἀκέραιοι τέκνα Θεοῦ ἄμωμα μέσον γενεᾶς σκολιᾶς καὶ διεστραμμένης ἐν οἷς φαίνεσθε ὡς φωστῆρες ἐν κόσμῳ
Therefore, my dearly beloved, just as you have been obeying, not only in my presence, but now all the more in my absence, continue to work for* your salvation with fear and trembling. For it is God working in you both to do and to will according to His good pleasure. Do all things without murmurings and disputing, that you may be blameless and innocent children of God; unblemished in the midst of a crooked and perverse generation, wherein you shine as lights in the world.
* κατεργάζεσθε katergazomai — bring about, work-towards: work to the end of
St. Paul makes clear that works don't save. But He makes equally clear our works are God's works—for the Redeemed believer. God working in us. It is not of ourselves. Grace is the fuel, God guides our hand by His Spirit.
Hence St. Paul's imagery of running a race,fighting and keeping the faith (2 Tim 4:7) is not meaningless, and there is something to strive for: salvation. Salvation is completed in that it has already been merited, but we are not strictly 'saved' until we are out of the pit of this sinful world, and in heaven. BUt we are still constantly in the process of "being saved" (1 Cor 1:18) by God.
Works and good deeds and a strong faith are the works of God, not man. Man merely co-operates with the grace, the gift of the power, to do good toward His salvation. His crown, which he must fight for (James 1:12; Jn 14:23; Rev 3:11; Lam 5:16; cf. Rev 3:11; 1 Tim 4:16).
St. Paul says we must compete for the crown of salvation: 1 Corinthians 9:25. And even that unless you keep to the rules, you cannot recieve your crown: 2 Timothy 2:5 cf. 1 John 2:4
St. John writes that we must work for it: 2 John 1:8. cf. Rom 2:7. And that ceasing to remain faithful to the commandments of Christ means we lose God (2 John 1:8).
It's simply that all working, doing, believing is by the grace of God, so that no one may boast that he accomplished anything not accomplished by God in truth.
God's grace and works are by no means mutually exclusive: God works in us to achieve our salvation. He affects a real change, not a ficticious one. His grace both allows and empowers us to achieve the end of salvation.
Grace vs. works or faith vs. works are false, unscriptural dichotomies. In fact, it is one taught against by St. James:
Τί τὸ ὄφελος ἀδελφοί μου ἐὰν πίστιν λέγῃ τις ἔχειν ἔργα δὲ μὴ ἔχῃ μὴ δύναται ἡ πίστις σῶσαι αὐτόν ἐὰν ἀδελφὸς ἢ ἀδελφὴ γυμνοὶ ὑπάρχωσιν καὶ λειπόμενοι τῆς ἐφημέρου τροφῆς εἴπῃ δέ τις αὐτοῖς ἐξ ὑμῶν Ὑπάγετε ἐν εἰρήνῃ θερμαίνεσθε καὶ χορτάζεσθε μὴ δῶτε δὲ αὐτοῖς τὰ ἐπιτήδεια τοῦ σώματος τί τὸ ὄφελος οὕτως καὶ ἡ πίστις ἐὰν μὴ ἔχῃ ἔργα νεκρά ἐστιν καθ’ ἑαυτήν Ἀλλ’ ἐρεῖ τις Σὺ πίστιν ἔχεις κἀγὼ ἔργα ἔχω* δεῖξόν μοι τὴν πίστιν σου χωρὶς τῶν ἔργων κἀγώ σοι δείξω ἐκ τῶν ἔργων μου τὴν πίστιν σὺ πιστεύεις ὅτι εἷς ἐστιν ὁ Θεός καλῶς ποιεῖς καὶ τὰ δαιμόνια πιστεύουσιν καὶ φρίσσουσιν Θέλεις δὲ γνῶναι ὦ ἄνθρωπε κενέ ὅτι ἡ πίστις χωρὶς τῶν ἔργων ἀργή ἐστιν Ἀβραὰμ ὁ πατὴρ ἡμῶν οὐκ ἐξ ἔργων ἐδικαιώθη ἀνενέγκας Ἰσαὰκ τὸν υἱὸν αὐτοῦ ἐπὶ τὸ θυσιαστήριον βλέπεις ὅτι ἡ πίστις συνήργει τοῖς ἔργοις αὐτοῦ καὶ ἐκ τῶν ἔργων ἡ πίστις ἐτελειώθη καὶ ἐπληρώθη ἡ γραφὴ ἡ λέγουσα Ἐπίστευσεν δὲ Ἀβραὰμ τῷ Θεῷ καὶ ἐλογίσθη αὐτῷ εἰς δικαιοσύνην καὶ φίλος Θεοῦ ἐκλήθη ὁρᾶτε ὅτι ἐξ ἔργων δικαιοῦται ἄνθρωπος καὶ οὐκ ἐκ πίστεως μόνον Ὁμοίως δὲ καὶ Ῥαὰβ ἡ πόρνη οὐκ ἐξ ἔργων ἐδικαιώθη ὑποδεξαμένη τοὺς ἀγγέλους καὶ ἑτέρᾳ ὁδῷ ἐκβαλοῦσα ὥσπερ γὰρ τὸ σῶμα χωρὶς πνεύματος νεκρόν ἐστιν οὕτως καὶ ἡ πίστις χωρὶς ἔργων νεκρά ἐστιν
What does it profit, my brethren, if any say he has faith, but no works? Can such faith save him? Now if a brother or sister is without clothes, and lacking daily food, and any of you says to them, Go in peace; be warm and well fed! but give not that which they have need of for the body, what would it profit? So also faith, by itself, without works, is dead. But someone may say, You have faith and I have works.* Show me your faith without works, and I will show you my faith by my works.
You believe that God is one: you do well! The demons believe also, and shudder! O foolish man, [must I show you] that faith without works is worthless? Was not our father Abraham justified by works, when he offered his son Isaacon the altar? You see that faith was working together with works, and his faith was perfected by the works; and the Scripture was fulfilled which says, Abraham believed God and it was counted for him as righteousness. And he was called the friend of God. [From this we see] that a man is justified by works, and not by faith alone. In the same way, was not Rahab the prostitute justified by works when she welcomed the messengeres adn sent them off another way? For as the body without the spirit is dead, so is faith without works dead.
* the false dichotomy